Loading unit for surgical instruments with low profile pushers

ABSTRACT

A loading unit for engagement with a surgical instrument, and including single and double retention slots, is discloses. At least one single retention cavity includes a first retention guiding surface configured to engage a first pusher guiding surface of a single pusher retained therein, a second retention guiding surface configured to engage a second pusher guiding surface of a single pusher retained therein, a third retention guiding surface configured to engage a third pusher guiding surface of a single pusher retained therein, and a fourth retention guiding surface configured to engage a fourth pusher guiding surface a the single pusher retained therein. At least one double retention cavity includes a first retention guiding surface configured to engage a first pusher guiding surface of a double pusher retained therein, and a second retention guiding surface configured to engage a second pusher guiding surface of a double pusher retained therein.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No. 16/856,561, filed on Apr. 23, 2020, now U.S. Pat. No. 11,317,918, which is a continuation of U.S. patent application Ser. No. 15/343,900, filed on Nov. 4, 2016, now U.S. Pat. No. 10,631,857, the entire contents of each of which being incorporated by reference herein.

BACKGROUND

The present disclosure relates generally to instruments for surgically joining tissue and, more specifically, to a loading unit for surgical instruments with low profile pushers.

Various types of surgical instruments used to surgically join tissue are known in the art, and are commonly used, for example, for closure of tissue or organs in transection, resection, anastomoses, for occlusion of organs in thoracic and abdominal procedures, and for electrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical stapling instrument, which may include an anvil assembly, a cartridge assembly for supporting an array of surgical fasteners, an approximation mechanism for approximating the cartridge and anvil assemblies, and a firing mechanism for ejecting the surgical fasteners from the cartridge assembly.

Using a surgical instrument, it is common for a surgeon to approximate the anvil and cartridge members. Next, the surgeon can fire the instrument to emplace surgical fasteners in tissue. Additionally, the surgeon may use the same instrument or a separate instrument to cut the tissue adjacent or between the row(s) of surgical fasteners.

Additionally, a loading unit (e.g., a single use loading unit or a disposable loading unit) may be attached to an elongated or endoscopic portion of a surgical stapling instrument. Such loading units allow surgical stapling instruments to have greater versatility, for example. The loading units may be configured for a single use, and/or may be configured for multiple uses.

Further, end effectors and/or loading units are generally limited in size by various components contained therein. That is, while there may be a need for end effectors and/or loading units having diameters that are smaller than those typically available, the diameter of the end effector and/or loading unit is typically limited by the size, geometry and/or orientation of the pushers, I-beam, actuation sled, and fasteners, for example, contained therein.

SUMMARY

The present disclosure relates to a loading unit configured for engagement with a surgical instrument. The loading unit including a proximal body portion, an end effector, an actuation sled, single pushers, double pushers, single retention cavities and double retention cavities. The proximal body portion defines a longitudinal axis. The end effector is disposed in mechanical cooperation with the proximal body portion, and includes a cartridge assembly and an anvil assembly. One of the cartridge assembly and the anvil assembly is movable with respect to the other of the cartridge assembly and the anvil assembly between an open position and an approximated position. The cartridge assembly is configured to house fasteners therein. The actuation sled is longitudinally translatable within the cartridge assembly. The single pushers are disposed within the cartridge assembly. Each single pusher is configured to engage one fastener. At least one singe pusher includes a body portion disposed parallel to the longitudinal axis, and a first lateral extension extending perpendicularly from the body portion in a first direction. The first lateral extension includes a first pusher guiding surface and a second pusher guiding surface. A second lateral extension extends perpendicularly from the body portion in a second, opposite direction and includes a third pusher guiding surface and a fourth pusher guiding surface. The double pushers are disposed within the cartridge assembly, and is double pusher is configured to engage two fasteners. At least one double pusher includes a first body portion, a second body portion, and a bridge interconnecting the first body portion and the second body portion. The bridge includes a first pusher guiding surface and a second pusher guiding surface. The single retention cavities are disposed within the cartridge assembly, and are each configured to retain one single pusher therein. At least one single retention cavity includes a first retention guiding surface configured to engage the first pusher guiding surface of the single pusher retained therein, a second retention guiding surface configured to engage the second pusher guiding surface of the single pusher retained therein, a third retention guiding surface configured to engage the third pusher guiding surface of the single pusher retained therein, and a fourth retention guiding surface configured to engage the fourth pusher guiding surface of the single pusher retained therein. The double retention cavities are disposed within the cartridge assembly, and each double retention cavity is configured to retain one double pusher therein. At least one double retention cavity includes a first retention guiding surface configured to engage the first pusher guiding surface of the double pusher retained therein, and a second retention guiding surface configured to engage the second pusher guiding surface of the double pusher retained therein.

In disclosed embodiments, the first pusher guiding surface of the at least one single pusher may be disposed on a proximal face of the first lateral extension, and the second pusher guiding surface of the at least one single pusher may be disposed on a distal face of the first lateral extension. It is also disclosed that the third pusher guiding surface of the at least one single pusher may be disposed on a proximal face of the second lateral extension, and the fourth pusher guiding surface of the at least one single pusher may be disposed on a distal face of the second lateral extension. Additionally, it is disclosed that the first pusher guiding surface of the at least one double pusher may be disposed on a proximal face of the bridge. It is further disclosed that the second pusher guiding surface of the at least one double pusher may be disposed on a distal face of the bridge.

In embodiments, the at least one single pusher further may include a first camming surface configured to be engaged by a first wedge of the actuation sled. It is also disclosed that the at least one single pusher further may include a second camming surface configured to be engaged by a second wedge of the actuation sled. It is further disclosed that the at least one double pusher may further include a first camming surface configured to be engaged by the first wedge of the actuation sled. It is additionally disclosed that the at least one double pusher may further include a second camming surface configured to be engaged by the second wedge of the actuation sled.

In disclosed embodiments, the at least one single pusher may further include a first camming surface configured to be engaged by a first wedge of the actuation sled, and the first camming surface may be disposed beneath the first pusher guiding surface of the at least one single pusher.

It is further disclosed that an outer-most diameter of the end effector may be about 12 mm with the end effector in the approximated position. It is also disclosed that the end effector may include fasteners retained at least partially within the cartridge assembly, and that at least one fastener may have a height of about 5 mm.

In embodiments, the at least one single retention slot may define a plus sign-like shape at a tissue-contacting surface of the cartridge assembly. It is also disclosed that the at least one double retention slot may define an H-like shape at the tissue-contacting surface of the cartridge assembly.

In disclosed embodiments, the cartridge assembly may include a knife channel, and opposing lateral sides of the knife may include single pushers and double pushers.

It is also disclosed that a width of the at least one single pusher may be equal to a width of the at least one double pusher.

The present disclosure also relates to an end effector configured for use with a surgical instrument. The end effector includes a cartridge assembly, an anvil assembly, an actuation sled, a plurality of pushers, and a plurality of fasteners. One of the cartridge assembly and the anvil assembly is movable with respect to the other of the cartridge assembly and the anvil assembly between an open position and an approximated position. The actuation sled is longitudinally translatable within the cartridge assembly. The plurality of pushers is disposed at least partially within the cartridge assembly and is configured to be selectively engaged by the actuation sled. The plurality of fasteners is retained at least partially within the cartridge assembly. Each fastener of the plurality of fasteners is disposed in contact with one pusher of the plurality of pushers, and each fastener of the plurality of fasteners includes a height of about 5 mm. An outer-most diameter of the end effector is about 12 mm.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the present disclosure are illustrated herein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a surgical instrument in accordance with an embodiment of the present disclosure;

FIG. 2 is a perspective view of a loading unit having an end effector in accordance with the present disclosure illustrating the end effector in an open position;

FIG. 3 is a side view of the loading unit of FIG. 2 illustrating the end effector in an approximated position;

FIG. 4 is a distal end view of a portion of the end effector of FIG. 3;

FIG. 5 illustrates the area of detail indicated in FIG. 2;

FIG. 6 is a perspective view of a portion of a cartridge assembly of the end effector of FIGS. 1-5 including a plurality of fasteners engaged therewith;

FIG. 7 is an assembly view of the end effector of FIGS. 1-6;

FIG. 8 is a perspective view of two single pushers and two double pushers of the end effector of FIGS. 1-7;

FIG. 9 is a perspective view of one single pusher and one double pusher of FIG. 8;

FIG. 10 is a front view of the single pusher of FIG. 9;

FIG. 11 is a front view of the double pusher of FIG. 9;

FIG. 12 illustrates the area of detail indicated in FIG. 6;

FIG. 13 is a cut-away view of a portion of the cartridge assembly of the end effector in accordance with the present disclosure;

FIG. 14 is a cut-away view of portions of the end effector taken along line 14-14 of FIG. 4;

FIG. 15 is a cut-away view of portions of the end effector taken along line 15-15 of FIG. 4;

FIG. 16 is a cut-away view of portions of the end effector taken along line 16-16 of FIG. 4;

FIG. 17 is a cut-away view of portions of the end effector taken along line 17-17 of FIG. 4; and

FIG. 18 is a cut-away view of portions of the end effector taken along line 18-18 of FIG. 4.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, loading unit for use therewith, and cartridge assembly for use therewith, are described in detail with reference to the drawings, wherein like reference numerals designate corresponding elements in each of the several views. As is common in the art, the term “proximal” refers to that part or component closer to the user or operator, e.g., surgeon or physician, while the term “distal” refers to that part or component farther away from the user.

A surgical instrument of the present disclosure is indicated as reference numeral 100 in FIG. 1. Generally, surgical instrument 100 includes a handle assembly 110, an elongated portion 120 extending distally from handle assembly 110, and a loading unit 200 disposed adjacent a distal end of elongated portion 120. While FIG. 1 illustrates surgical instrument 100 including a handle assembly including a movable handle 112 and a stationary handle, other types of handles can be used such as, for example, powered, motor-driven, hydraulic, ratcheting, etc. As used herein, “handle assembly” encompasses all types of handle assemblies. Loading unit 200 is releasably attachable to elongated portion 120 of surgical instrument 100, e.g., to allow surgical instrument 100 to have greater versatility. This arrangement allows the clinician to select a particular loading unit 200 for a given procedure. As used herein, “loading unit” encompasses both single use loading units (“SULU”) and disposable loading units (“DLU”). Additionally or alternatively, surgical instrument 100 may have a cartridge that is removable and replaceable in the reusable jaws of the surgical instrument.

Examples of loading units for use with a surgical stapling instrument are disclosed in commonly-owned U.S. Pat. No. 5,752,644 to Bolanos et al., the entire contents of which are hereby incorporated by reference herein. Further details of an endoscopic surgical stapling instrument are described in detail in commonly-owned U.S. Pat. No. 6,953,139 to Milliman et al., the entire contents of which are hereby incorporated by reference herein.

In surgical instrument 100 in accordance with the present disclosure, a firing rod (not shown) is moved distally in response to actuation of handle assembly 110 to deploy fasteners 600 (FIGS. 6 and 7). With reference to the embodiment illustrated in FIG. 1, at least a partial actuation of movable handle 112 translates the firing rod longitudinally. Distal translation of the firing rod causes distal translation of a clamping member 500 (FIG. 7) to approximate at least one jaw member with respect to the other, as discussed in further detail below. Distal translation of clamping member 500 also causes corresponding translation of an actuation sled 520, which engages pushers 700 (FIG. 7) in a sequential manner, and which results in pushers 700 moving within retention cavities 1000, 1100 (FIG. 5) of a cartridge assembly 400 to cause the ejection of fasteners 600 therefrom, as discussed in further detail below (FIG. 7).

With reference to FIGS. 2-7, loading unit 200 according to the present disclosure is shown. Loading unit 200 includes a proximal body portion 210 defining a longitudinal axis “A-A,” and a tool assembly or end effector 220 including a first jaw member or anvil assembly 300, and a second jaw member or cartridge assembly 400. Cartridge assembly 400 includes a cartridge 408 disposed within a cartridge channel 409 (FIG. 7). Proximal body portion 210 is configured to be removably attached to elongated portion 120 of surgical instrument 100 as will be discussed in detail hereinbelow. Additionally, end effector 220 is pivotable with respect to proximal body portion 210 (and longitudinal axis “A-A”).

Various features of loading unit 200 disclosed herein allow loading unit 200 to have a relatively small diameter “d” (e.g., about 12 mm) as compared with more conventional instruments having diameters of about 15 mm. As shown in FIGS. 3 and 4, the diameter “d” of the loading unit 200, and end effector 220 in particular, is measured between a radially outer-most wall of anvil assembly 300 and a radially outer-most wall of cartridge assembly 400. Such a low profile allows loading unit 200 to be inserted into trocars or other access devices having similar inner diameters. It is contemplated that the presently disclosed end effector 220 can be inserted into openings in body tissue (e.g., incision or naturally occurring orifice) having a comparable diameter. As can be appreciated, such low profile loading units 200 are useful in pediatric surgeries and/or other tissue locations, for example.

Additionally, in the illustrated embodiments, a proximal portion 212 of proximal body portion 210 of loading unit 200 is sized and configured to engage elongated portion 120 of surgical instrument 100 (FIG. 1). It is envisioned that elongated portion 120 of surgical instrument 100 includes the same, similar or larger diameter (e.g., about 12 mm) than the diameter “d” of loading unit 200, thus enabling greater versatility.

More particularly, with reference to FIGS. 2 and 3, an insertion tip 202 of loading unit 200 is linearly insertable into the distal end of elongated portion 120 of surgical instrument 100 (FIG. 1). Nubs 204 of insertion tip 202 move linearly through slots (not shown) formed adjacent the distal end of elongated portion 120. Subsequently, loading unit 200 is rotated about the longitudinal axis “A-A” with respect to elongated portion 120 such that nubs 204 move transversely with respect to longitudinal axis “A-A” through the slots within elongated portion 120. Additionally, during engagement of loading unit 200 and elongated portion 120, the firing rod of handle assembly 110 engages a portion of a drive bar 510 (FIG. 7) of loading unit 200. As shown in FIG. 7, a distal end of drive bar 510 is coupled to clamping member 500.

With reference to FIG. 7, clamping member 500 includes an I-shaped cross-section, including a top portion 502, which is configured to engage anvil assembly 300 (FIG. 2), a bottom portion 504, which is configured to engage cartridge assembly 400, and a vertical portion 503, which connects top portion 502 and bottom portion 504, and which may include a cutting edge 506 on its distal or leading surface. Further, distal advancement of clamping member 500 through end effector 220 causes bottom portion 504 to contact a camming surface 402 (FIG. 3) of cartridge assembly 400. Continued distal advancement of clamping member 500 thus causes cartridge assembly 400 to pivot with respect to anvil assembly 300 from its open position (FIG. 2) toward its approximated position (FIG. 3). It is further envisioned that anvil assembly 300 may pivot with respect to a stationary cartridge assembly 400. Thus, a predetermined amount of distal travel of the firing rod, and thus drive bar 510, causes approximation of the jaw members. Additionally, cutting edge 506 of clamping member 500, if included on clamping member 500, severs tissue disposed between the jaw members (after the tissue has been fastened) as cutting edge 506 travels through a knife channel 401 of cartridge assembly 400 (FIGS. 5 and 6). In embodiments where end effector 220 is curved, knife channel 401 may define a longitudinal axis.

With further regard to actuation sled 520, distal translation of actuation sled 520 sequentially engages pushers 700, and causes pushers 700 to move in the general direction of arrow “B” (FIG. 7) and eject fasteners 600 toward anvil assembly 300. As noted above, subsequent to the ejection of fasteners 600, cutting edge 506 of clamping member 500 may sever the stapled tissue.

With particular reference to FIGS. 7 and 14-18, further details of actuation sled 520 are disclosed. Actuation sled 520 includes four angled wedges 524 a, 524 b, 524 c, 524 d configured to contact an angled or camming surface 742, 752, 842, 852 of pushers 700, as discussed below. Engagement between wedges 524 a, 524 b, 524 c, 524 d of actuation sled 520 and camming surfaces 742, 752, 842, 852 of pushers 700 causes pushers 700 to move in the general direction of arrow “B” (FIG. 7), which results in ejection of fasteners 600 from retention cavities 1000, 1100 of cartridge assembly 400, and toward respective staple-forming pockets of anvil assembly 300 (e.g., through tissue held between the jaw members).

Referring now to FIGS. 8-13, further details of pushers 700 are disclosed. Generally, pushers 700 include a plurality of single pushers 710 and a plurality of double pushers 800. Each single pusher 710 is retained within a first or single retention cavity 1000 of cartridge assembly 400, and each double pusher 800 is retained within a second or double retention cavity 1100 of cartridge assembly 400.

With particular reference to FIG. 8, single pushers 710 include a first single pusher 710 a and a second single pusher 710 b, and double pushers 800 include a first double pusher 800 a and a second double pusher 800 b. A plurality of first single pushers 710 a and a plurality of first double pushers 800 a are disposed on a first side of knife channel 401 of cartridge assembly 400, and a plurality of second single pushers 710 b and a plurality of second double pushers 800 b are disposed on a second side of knife channel 401 of cartridge assembly 400. Each single pusher 710 a is configured to engage a fastener 600 in a middle row on a first side of knife channel 401, and each single pusher 710 b is configured to engage a fastener 600 in a middle row on a second side of knife channel 401. Each double pusher 800 a is configured to engage a fastener 600 in an inner row and a fastener 600 in an outer row on the first side of knife channel 401, and each double pusher 800 b is configured to engage a fastener 600 in an inner row and a fastener 600 in an outer row on the second side of knife channel 401. First single pusher 710 a is a mirror image of second single pusher 710 b, and first double pusher 800 a is a mirror image of second double pusher 800 b. Accordingly, only the details of one single pusher 710 and one double pusher 800 are discussed herein, and are generally referred to as single pusher 710 and double pusher 800.

Single pusher 710 includes a body portion 712, a first lateral extension 720, a second lateral extension 730, a first camming member 740, and a second camming member 750. Single pusher 710 is positioned within cartridge assembly 400 such that body portion 712 is parallel to the longitudinal axis “A-A.” Additionally, body portion 712 includes an arcuate proximal edge 713 and an arcuate distal edge 714, which are each configured to engage corresponding portions of first retention cavity 1000. The engagement between proximal edge 713 and distal edge 714 of body portion 712 with first retention cavity 1000 may help guide and/or align the travel of single pusher 710 with respect to cartridge assembly 400.

First lateral extension 720 extends perpendicularly from body portion 712 in a first direction. Second lateral extension 730 extends perpendicularly from body portion 712 in a second, opposite direction. First camming member 740 extends proximally from first lateral extension 720, and second camming member 750 extends proximally from second lateral extension 730.

An upper channel 715 of body portion 712 of single pusher 710 is configured and dimensioned to engage a backspan 602 of fastener 600 (FIG. 12). Upper channel 715 of body portion 712 includes an arcuate cross-section, which helps to optimize engagement with an arcuate portion of backspan 602, for example.

With reference to FIGS. 9 and 10, first camming member 740 includes a first camming surface 742, and second camming member 750 includes a second camming surface 752. In the orientation illustrated in FIGS. 9 and 10, first camming surface 742 is configured to be engaged by wedge 524 a of actuation sled 520, and second camming surface 752 is configured to be engaged by wedge 524 b of actuation sled 520 (see FIG. 16). In use, distal movement of actuation sled 520 with respect to cartridge assembly 400 causes wedges 524 a, 524 b of actuation sled 520 to contact first camming surface 742 and second camming surface 752, respectively, which causes single pusher 710 to move toward anvil assembly 300. This movement of single pusher 710 causes a corresponding fastener 600 to be ejected from first retention cavity 1000 of cartridge assembly 400.

With continued reference to FIGS. 9 and 10, first lateral extension 720 includes an upper surface 722, and second lateral extension 730 includes an upper surface 732. Upper surface 722 of first lateral extension 720 is a non-linear, step-like surface. Generally, a first portion 722 a of upper surface 722, which is close to body portion 712, is higher (or closer to a tissue-contacting surface 410 of cartridge assembly 400) than a second portion 722 b of upper surface 722, which is farthest from body portion 712. That is, first portion 722 a of upper surface 722 is closer to knife channel 401 than second portion 722 b of upper surface 722. Additionally, a first portion 732 a of upper surface 732, which is close to body portion 712, is lower (or farther from tissue-contacting surface 410 of cartridge assembly 400) than a second portion 732 b of upper surface 732, which is farthest from body portion 712. Further, second portion 722 b of upper surface 722 of first lateral extension 720 is lower than upper channel 715 of body portion 712, and second portion 732 b of upper surface 732 of second lateral extension 730 is higher than upper channel 715 of body portion 712. Also, in either orientation of single pusher 710, the upper surface 722 or 732 of the lateral extension 720 or 730, respectively, that is closest to knife channel 401 is higher than the other upper surface 732 or 722.

With reference to FIGS. 8, 12 and 13, pusher 710 is configured to engage and/or be guided by first retention cavity 1000 in a plurality of particular locations. In particular, single pusher 710 includes a first pusher guiding surface or first guiding surface 782 disposed on a proximal surface of first lateral extension 720, a second pusher guiding surface or second guiding surface 784 disposed on a distal surface of first lateral extension 720, a third pusher guiding surface or third guiding surface 786 disposed on a proximal surface of second lateral extension 730, and a fourth pusher guiding surface or fourth guiding surface 788 disposed on a distal surface of second lateral extension 730.

First retention cavity 1000 includes corresponding guiding surfaces, which are configured to engage and/or guide the movement of single pusher 710 retained at least partially therein. As shown in FIG. 12, first retention cavity 1000 defines a plus sign-like shape at tissue-contacting surface 410 of cartridge assembly 400. As shown in FIG. 13, the shape of first retention cavity 1000 beneath tissue-contacting surface 410 is different from the plus sign-like shape of first retention cavity 1000 at tissue-contacting surface 410 of cartridge assembly 400.

With continued reference to FIGS. 12 and 13, first retention cavity 1000 is defined in part by a first retention guiding surface or first guiding surface 1002 configured to engage or guide first guiding surface 782 of single pusher 710, a second retention guiding surface or second guiding surface 1004 configured to engage or guide second guiding surface 784 of single pusher 710, a third retention guiding surface or third guiding surface 1006 configured to engage or guide third guiding surface 786 of single pusher 710, and a fourth retention guiding surface or fourth guiding surface 1008 configured to engage or guide fourth guiding surface 788 of single pusher 710.

With particular reference to FIGS. 8, 9, and 11, double pusher 800 includes a first body portion 810, a second body portion 820, a bridge 830, a first camming member 840, and a second camming member 850. Double pusher 800 is positioned within cartridge assembly 400 such that first body portion 810 and second body portion 820 are parallel to the longitudinal axis “A-A.” Additionally, first body portion 810 includes an arcuate proximal edge 813 and an arcuate distal edge 814, and second body portion 820 includes an arcuate proximal edge 823 and an arcuate distal edge 824. Each proximal edge 813, 823 and distal edge 814, 824 is configured to engage corresponding portions of second retention cavity 1100 to help guide and/or align the travel of double pusher 800 with respect to cartridge assembly 400.

Bridge 830 extends perpendicularly between and interconnects first body portion 810 and second body portion 820. First camming member 840 extends proximally from a first lateral portion 832 of bridge 830, and second camming member 850 extends proximally from a second lateral portion 834 of bridge 830 (see FIG. 11).

An upper channel 815 of first body portion 810 and an upper channel 825 of second body portion 820 of double pusher 800 are each configured and dimensioned to engage backspan 602 of fastener 600. Upper channels 815 and 825 include an arcuate cross-section, which helps to optimize engagement with an arcuate portion of backspan 602, for example.

With continued reference to FIG. 11, first camming member 840 includes a first camming surface 842, and second camming member 850 includes a second camming surface 852. In the orientation illustrated in FIG. 11, first camming surface 842 is configured to be engaged by wedge 524 a of actuation sled 520, and second camming surface 852 is configured to be engaged by wedge 524 b of actuation sled 520 (see FIG. 7). As discussed above, first camming surface 742 of first camming member 740 of single pusher 710 is also configured to be engaged by wedge 542 a of actuation sled 520, and second camming surface 752 of second camming member 750 of single pusher 710 is also configured to be engaged by wedge 524 b of actuation sled 520. Further, wedge 524 d of actuation sled 520 is configured to engage a camming surface of single pusher 710 b that corresponds to first camming surface 742 of single pusher 710 a, and a camming surface of double pusher 800 b that corresponds to first camming surface 842 of double pusher 800 a (i.e., a camming surfaces that are farthest from knife channel 401) (see FIG. 18). Additionally, wedge 524 c of actuation sled 520 is configured to engage a camming surface of single pusher 710 b that corresponds to second camming surface 752 of single pusher 710 a, and a camming surface of double pusher 800 b that corresponds to second camming surface 852 of double pusher 800 a (i.e., a camming surfaces that are closest to knife channel 401) (see FIG. 18).

In use, distal movement of actuation sled 520 with respect to cartridge assembly 400 causes wedges 524 a, 524 b of actuation sled 520 to contact first camming surface 842 and second camming surface 852 of double pusher 800, respectively, which causes double pusher 800 to move in the general direction of arrow “B” (FIG. 7). This movement of double pusher 800 causes two corresponding fasteners 600 to be ejected from second retention cavity 1100 of cartridge assembly 400.

As discussed above, distal movement of actuation sled 520 with respect to cartridge assembly 400 also causes wedges 524 a, 524 b of actuation sled 520 to contact first camming surface 742 and second camming surface 752 of single pusher 710, respectively, which causes single pusher 710 to move in the general direction of arrow “B,” which causes a corresponding fastener 600 to be ejected from first retention cavity 1000 of cartridge assembly 400. Further, distal movement of actuation sled 520 with respect to cartridge assembly 400 also causes wedges 524 d and 524 c of actuation sled 520 (FIG. 18) to contact corresponding camming wedges of single pusher 710 b, which also results in corresponding fasteners 600 being ejected from their respective retention cavities 1000 of cartridge assembly 400. When positioned in the respective retention cavities 1000, 1100 camming surface 742 of single pusher 710 is longitudinally aligned with camming surface 842 of double pusher 800, and camming surface 752 of single pusher 710 is longitudinally aligned with camming surface 852 of double pusher 800.

Referring now to FIGS. 9 and 11, bridge 830 includes an upper surface 836. In the illustrated embodiment, upper surface 836 of bridge 830 is non-linear. Generally, a first portion 836 a of upper surface 836, which is close to first body portion 810, is lower than a second portion 836 b of upper surface 836, which is closest to second body portion 820. Additionally, as shown in FIG. 11, upper channel 815 of first body portion 810 is lower than upper channel 825 of second body portion 820.

With reference to FIGS. 10 and 11, a height “h1d” of upper channel 815 of first body portion 810 of double pusher 800 with respect to a lower surface 802 of double pusher 800 is smaller than a height “h1s” of upper channel 715 of body portion 712 of single pusher 710 with respect to a lower surface 711 of single pusher 710. Further, height “h1s” is smaller than a height “h2d” of upper channel 825 of second body portion 820 of double pusher 800 with respect to lower surface 802 of double pusher 800.

It is disclosed that “h1d” is between about xx mm and about xx mm, that “h1s” is between about xx mm and about xx mm, and that “h2d” is between about 1.40 mm and about 1.60 mm (e.g., equal to about 1.52 mm).

In disclosed embodiments, a width “ws” of single pusher 710 is equal to or approximately equal to a width “wd” of double pusher 800 (see FIGS. 10 and 11).

Further, in either orientation of double pusher 800, the upper channel of the body portion that is closest to knife channel 401 is higher than the other upper channel with respect to cartridge channel 409.

With reference to FIGS. 11-13, double pusher 800 is configured to engage and/or be guided by second retention cavity 1100 in a plurality of particular locations. In particular, double pusher 800 includes a first pusher guiding surface or first guiding surface 882 disposed on a proximal surface of bridge 830, and a second pusher guiding surface or second guiding surface 884 disposed on a distal surface of bridge 830.

Second retention cavity 1100 includes corresponding guiding surfaces, which are configured to engage and/or guide the movement of double pusher 800 retained at least partially therein. As shown in FIG. 12, second retention cavity 1100 defines an H-like shape at tissue-contacting surface 410 of cartridge assembly 400. As shown in FIG. 13, the shape of second retention cavity 1100 beneath tissue-contacting surface 410 is different from the H-like shape of second retention cavity 1100 at tissue-contacting surface 410 of cartridge assembly 400. With reference to FIGS. 12 and 13, second retention cavity 1100 is defined in part by a first retention guiding surface or first guiding surface 1102 configured to engage or guide first guiding surface 882 of double pusher 800, and a second retention guiding surface or second guiding surface 1104 configured to engage or guide second guiding surface 884 of double pusher 800.

The orientation of various parts of single pusher 710 and double pusher 800 enable diameter “d” (FIGS. 2 and 3) of loading unit 200 to be smaller than more conventional instruments. For example, diameter “d” of loading unit 200 of the present disclosure may be approximately 12 mm, while the diameter of more conventional loading units may be approximately 15 mm. In other types of loading units, the body portions of the pushers (i.e., the portions that directly support fasteners thereon) include guiding surfaces, which engage corresponding guiding surfaces within retention slots. In the present disclosure, and as discussed above, the guiding surfaces of the pushers are included on lateral extensions 720, 730 of single pusher 710 and on bridge 830 of double pushers 800. Since the guiding surfaces are not included (or not solely included) on the body portions of pushers 700, the overall height of pushers 700 can be reduced with respect to previous types of pushers. Since the height of pushers 700 (i.e., single pushers 710 and double pushers 800) is relatively small, the amount of distance that pushers 700 can travel (i.e., “pusher stroke”) is relatively large. Such a large “pusher stroke” allows larger fasteners 600 (e.g., having a height of about 5 mm) to be used in connection with cartridge assembly 400.

The present disclosure also includes using fasteners 600 having the same height as each other, and/or fasteners 600 having a different height from other fasteners 600. For example, fasteners 600 that are located farthest from knife channel 401 of cartridge assembly 400 may have a larger height than fasteners 600 located closest to knife channel 401. The stepped configuration of tissue-contacting surface 410 of cartridge assembly 400 may facilitate the use of fasteners 600 having different heights. Further details of fasteners having different heights, and a stepped tissue-contacting surface are disclosed in commonly-owned U.S. patent application Ser. No. 14/661,001 to Czernik, now U.S. Pat. No. 9,918,717, the entire contents of which are hereby incorporated by reference herein.

The present disclosure also includes methods of performing a surgical procedure using surgical instrument 100 and/or loading unit 200 disclosed herein. For example, a method including using loading unit 200 having a diameter of about 12 mm to eject fasteners having a height of about 5 mm is disclosed. Such methods also include inserting loading unit 200 at least partially through a trocar having a diameter of about 12 mm.

While the above description contains many specifics, these specifics should not be construed as limitations on the scope of the present disclosure, but merely as illustrations of various embodiments thereof. For example, a loading unit such as described above can be configured to work with a robotic surgical system, or a remotely actuated and controlled surgical system. Such a loading unit can have a removable and replaceable staple cartridge or one that is not removable and replaceable. Therefore, the above description should not be construed as limiting, but merely as exemplifications of various embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

1. (canceled)
 2. A pusher configured to engage a surgical fastener, the pusher comprising: a body portion including a bottom surface configured to be engaged by an actuation sled; a first lateral extension extending from a first longitudinal position of the body portion in a first direction, an upper-most surface of the first lateral extension disposed at a first height relative to the bottom surface of the body portion; and a second lateral extension extending from the first longitudinal position of the body portion in a second direction, the second direction being opposite from the first direction, an upper-most surface of the second lateral extension disposed at a second height relative to the bottom surface of the body portion, the second height being different from the first height.
 3. The pusher according to claim 2, wherein the bottom surface of the body portion includes a first camming surface configured to be engaged by a first wedge of the actuation sled.
 4. The pusher according to claim 3, wherein the bottom surface of the body portion includes a second camming surface configured to be engaged by a second wedge of the actuation sled.
 5. The pusher according to claim 2, wherein the first lateral extension extends perpendicularly from the body portion.
 6. The pusher according to claim 5, wherein the second lateral extension extends perpendicularly from the body portion.
 7. The pusher according to claim 5, wherein the bottom surface of the body portion includes a first camming surface configured to be engaged by a first wedge of the actuation sled, and the first camming surface is disposed at an acute angle relative to the body portion.
 8. The pusher according to claim 7, wherein the bottom surface of the body portion includes a second camming surface configured to be engaged by a second wedge of the actuation sled, and the first camming surface is disposed at an acute angle relative to the body portion.
 9. The pusher according to claim 2, wherein the body portion includes one single, uninterrupted fastener-contacting surface.
 10. The pusher according to claim 2, wherein the upper-most surface of the first lateral extension is in contact with the body portion.
 11. The pusher according to claim 10, wherein the upper-most surface of the second lateral extension is spaced from the body portion.
 12. The pusher according to claim 2, wherein the upper-most surface of the second lateral extension is spaced from the body portion.
 13. A pusher configured to engage a surgical fastener, the pusher comprising a body portion; a first lateral extension extending from the body portion in a first direction, an upper-most surface of the first lateral extension being in contact with the body portion; and a second lateral extension extending from the body portion in a second direction, the second direction being opposite from the first direction, an upper-most surface of the second lateral extension being spaced from the body portion.
 14. The pusher according to claim 13, wherein the body portion includes one single, uninterrupted fastener-contacting surface.
 15. The pusher according to claim 13, wherein the body portion includes a first camming surface configured to be engaged by a first wedge of an actuation sled.
 16. The pusher according to claim 15, wherein the first camming surface is disposed at an acute angle relative to the body portion.
 17. The pusher according to claim 15, wherein the body portion includes a second camming surface configured to be engaged by a second wedge of the actuation sled.
 18. The pusher according to claim 13, wherein the first lateral extension extends perpendicularly from the body portion.
 19. The load pusher according to claim 18, wherein the second lateral extension extends perpendicularly from the body portion.
 20. The pusher according to claim 13, wherein the first lateral extension and the second lateral extension extend from substantially the same longitudinal position of the body portion. 